Hidden diversity and potential ecological function of phosphorus acquisition genes in widespread terrestrial bacteriophages.

Phosphorus (P) limitation of ecosystem processes is widespread in terrestrial habitats. While a few auxiliary metabolic genes (AMGs) in bacteriophages from aquatic habitats are reported to have the potential to enhance P-acquisition ability of their hosts, little is known about the diversity and potential ecological function of P-acquisition genes encoded by terrestrial bacteriophages. Here, we analyze 333 soil metagenomes from five terrestrial habitat types across China and identify 75 viral operational taxonomic units (vOTUs) that encode 105 P-acquisition AMGs. These AMGs span 17 distinct functional genes involved in four primary processes of microbial P-acquisition. Among them, over 60% (11/17) have not been reported previously. We experimentally verify in-vitro enzymatic activities of two pyrophosphatases and one alkaline phosphatase encoded by P-acquisition vOTUs. Thirty-six percent of the 75 P-acquisition vOTUs are detectable in a published global topsoil metagenome dataset. Further analyses reveal that, under certain circumstances, the identified P-acquisition AMGs have a greater influence on soil P availability and are more dominant in soil metatranscriptomes than their corresponding bacterial genes. Overall, our results reinforce the necessity of incorporating viral contributions into biogeochemical P cycling.

EGFR Inhibition Overcomes Resistance to FGFR4 Inhibition and Potentiates FGFR4 Inhibitor Therapy in Hepatocellular Carcinoma.

Aberrant activation of the FGF19-FGFR4 signaling pathway plays an essential role in the tumorigenesis of hepatocellular carcinoma (HCC). As such, FGFR4 inhibition has emerged as a novel therapeutic option for the treatment of HCC and has shown preliminary efficacy in recent clinical trials for patients exhibiting aberrant FGF19 expression. Resistance to kinase inhibitors is common in oncology, presenting a major challenge in the clinical treatment process. Hence, we investigated the potential mechanisms mediating and causing resistance to FGFR4 inhibition in HCC. Upon the successful establishment of a battery of cellular models developing resistance to FGFR4 inhibitors, we have identified the activation of EGFR, MAPK, and AKT signaling as the primary mechanisms mediating the acquired resistance. Combination of inhibitors against EGFR or its downstream components restored sensitivity to FGFR4 inhibitors. In parental HCC cell lines, EGF treatment also resulted in resistance to FGFR4 inhibitors. This resistance was effectively reverted by inhibitors of the EGFR signaling pathway, suggesting that EGFR activation is a potential cause of intrinsic resistance. We further confirmed the above findings in vivo in mouse xenograft tumor models. Genomic analysis of patient samples from The Cancer Genome Atlas confirmed that a segment of patients with HCC harboring FGF19 overexpression indeed exhibited increased activation of EGFR signaling. These findings conclusively indicate that both induced and innate activation of EGFR could mediate resistance to FGFR4 inhibition, suggesting that dual blockade of EGFR and FGFR4 may be a promising future therapeutic strategy for the treatment of FGF19-FGFR4 altered HCC.

Effect of IL-8 on hepatocellular carcinoma-associated metastasis by targeting MMP9 in mice.

Background: Interleukin-8 (IL-8) and matrix metallopeptidase 9 (MMP9) are overexpressed in hepatocellular carcinoma (HCC), and both are related to tumor metastasis, but whether they regulate HCC metastasis is still unclear. Methods: HCC orthotopic implantation and colonization mice models were established in vivo. Model mice were treated with IL-8 and or MMP9 inhibitors, protein kinase C (PKC) inhibitors, or extracellular regulated protein kinases 1/2 (ERK1/2) inhibitors. Liver metastasis and lung metastasis of model mice were confirmed by hematoxylin and eosin staining. The population of circulating tumor cells (CTCs) was detected by flow cytometry. The expression of MMP9 in tumor tissues was determined by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry. In vitro, HCC LM6 (HCCLM6) cells were treated with IL-8 combined PKC inhibitor or ERK1/2 inhibitor. The expression of MMP9 was confirmed by qRT-PCR and Western blot, and the activation of the PKC/ERK1/2 signaling pathway was confirmed by Western blot. Results: IL-8 promoted liver metastasis and lung metastasis in orthotopic transplantation model mice, increased the proportion of CTCs and promoted the expression of MMP9 in tumor tissues, but these effects were reversed by PKC inhibitor or ERK1/2 inhibitor. In vivo colonization experiments, IL-8 promoted tumor cell metastasis to the liver and lung, but the MMP9 inhibitor reversed the metastasis-promoting effect of IL-8. In cell experiments, IL-8 promoted the expression of p-PKC and p-ERK1/2 and inhibited the expression of PKC and ERK1/2; the promotion of MMP9 expression by IL-8 was reversed by PKC inhibitor or ERK1/2 inhibitor. Conclusions: IL-8 up-regulated the expression of MMP9 by activating the PKC/ERK1/2 signaling pathway, thereby promoting the metastasis and colonization of HCC.

Small molecule QF84139 ameliorates cardiac hypertrophy via activating the AMPK signaling pathway.

Cardiac hypertrophy is a common adaptive response to a variety of stimuli, but prolonged hypertrophy leads to heart failure. Hence, discovery of agents treating cardiac hypertrophy is urgently needed. In the present study, we investigated the effects of QF84139, a newly synthesized pyrazine derivative, on cardiac hypertrophy and the underlying mechanisms. In neonatal rat cardiomyocytes (NRCMs), pretreatment with QF84139 (1-10 µM) concentration-dependently inhibited phenylephrine-induced hypertrophic responses characterized by fetal genes reactivation, increased ANP protein level and enlarged cardiomyocytes. In adult male mice, administration of QF84139 (5-90 mg·kg-1·d-1, i.p., for 2 weeks) dose-dependently reversed transverse aortic constriction (TAC)-induced cardiac hypertrophy displayed by cardiomyocyte size, left ventricular mass, heart weights, and reactivation of fetal genes. We further revealed that QF84139 selectively activated the AMPK signaling pathway without affecting the phosphorylation of CaMKIIδ, ERK1/2, AKT, PKCε, and P38 kinases in phenylephrine-treated NRCMs and in the hearts of TAC-treated mice. In NRCMs, QF84139 did not show additive effects with metformin on the AMPK activation, whereas the anti-hypertrophic effect of QF84139 was abolished by an AMPK inhibitor Compound C or knockdown of AMPKα2. In AMPKα2-deficient mice, the anti-hypertrophic effect of QF84139 was also vanished. These results demonstrate that QF84139 attenuates the PE- and TAC-induced cardiac hypertrophy via activating the AMPK signaling. This structurally novel compound would be a promising lead compound for developing effective agents for the treatment of cardiac hypertrophy.